Cumene (isopropylbenzene) is an important feedstock chemical for the production of phenol, acetone, and alpha-methyl styrene. It is also used as an important raw material in the manufacture of pesticide intermediates such as p-cumidine, and finds application in the manufacture of cumene hydroperoxide and dicumyl peroxide, which are used as initiators in polymerization processes, such as grafting vinyl monomers onto polymer backbones, curing of resins and rubbers and the like. Further, it is used as a raw material in the production of acetophenone and diisoproplyl benzene; as a solvent for flats and resins; as a thinner for paints, enamels, and lacquers; and as a component in aviation gasolines.
Current technologies for production of cumene require use of large excess amounts of reactant benzene. Benzene is an expensive and carcinogenic organic reactant, therefore it is desirable to use either the least amount of benzene possible, or preferably, utilize a cheaper, less dangerous chemical than benzene. The technologies currently in use further require an energy-intensive, 2-step distillation process, requiring excess reactants and a necessary cooling time between the two steps.
Hydrocarbon production usually relies upon the catalytically driven chemical reaction between reactants and products, followed by energy-intensive distillation purification steps. Such separation by distillation is based on the differences in boiling points and volatilities of the individual components. When heat is applied, the vapor of a boiling mixture will be richer in the components having lower boiling points. Thus, when the vapor is cooled and condensed, the condensate contains more of the volatile components. Simultaneously, the primary mixture will contain more of the components that are less volatile. Recent technologies, such as catalytic distillation and reactive distillation, achieve catalytic reaction and continuous separation of unreacted reactant and products by distillation in one step, in a single catalytic distillation reactor column. The advantage of using a solid-catalyzed reaction, over a catalyst that acts as distillation packing inside the distillation column, is more pronounced when used in reactions limited by equilibrium. While these systems still require that reaction by-products be separated from the cumene, they now contain an energy-efficient distillation or fractionating step for separating unreacted benzene from the products.
However, these later technologies require the use of high pressures in the column to operate, given the fact that for distillation to take place at least part of the reacting mixture has to be in liquid phase. For reactor design that have a reaction temperature inherently limited by the boiling point of the liquid composition of the reacting components, then the use of higher column pressures increases the boiling temperature, which can be used to increase the yield of the reaction products by allowing the reactor to operate at a higher reaction temperature. However, if the column pressure is fixed in this type of design, then adding additional heat to the liquid composition only increases the amount of vapor being generated by boiling; rather than increasing the reactant's temperature.
It would be desirable and beneficial to utilize a production process that does not require high pressure (which requires specialized equipment and excess use of energy), and which utilizes only one separation column at atmospheric pressure, for reduction of cost, time, energy, and potential safety hazards.
Against this background, the present invention was developed.